Automated clinical analyzers are used in clinical chemistry laboratories to automatically process patient samples, determining the presence and/or concentration of various analytes in such samples. The degree of automation of such analyzers varies from instruments that simply automatically measure the concentration of a single sample placed in the instrument to systems that automatically process a large number of samples loaded onto the system by an operator.
System throughput, that is, the number of samples that can be analyzed per unit time, is an important consideration is automated systems. One of the factors affecting system throughput is the manner is which samples are loaded onto the system for analysis and removed from the system once the required analysis is completed. If the system must wait while an operator loads or removes samples, system throughput can be correspondingly affected. Thus, it is known in the art to utilize some mechanism or method which reduces the amount of time that a system must wait while an operator loads and unloads samples.
One approach is to place a number of individual samples onto a single turntable, such as is done on the Astra.RTM. Analyzer manufactured by Beckman Instruments Inc., Brea, Ca. The single turntable is then loaded onto the analyzer, a simple operation that helps to minimize the amount of time that the analyzer is idle. When all of the samples on the turntable have been analyzed, the entire turntable can be removed and replaced with another turntable holding samples requiring analysis. Although this technique has been found to be effective, it does require that the entire sample turntable be placed onto or removed from the analyzer at one time, regardless of the number of samples that are on the turntable. Thus, the amount of time that the analyzer operation is interrupted to load a turntable is the same whether or not the turntable is filled or has only a few samples.
Another approach is illustrated by the Paramax.RTM. Analytical System from American Dade. In The Paramax system, individual sample test tubes are loaded onto a loading carousel which is in turn loaded onto the system, similar to the Astra System just described. The sample test tubes are moved by an automatic transfer mechanism onto a transfer carousel where sample volumes are withdrawn and transferred to analysis cuvettes. The sample test tubes are then moved from the transfer carousel by another automatic transfer mechanism to an unloading carousel where they may then be unloaded by the system operator.
The Paramax system suffers from the same disadvantages noted above, namely that individual samples are loaded onto a large volume carousel and the carousel is then loaded onto the system. Thus, the versatility of the system is reduced. Furthermore, the Paramax system requires two automated sample handling mechanisms, each of which must handle individual glass sample test tubes, increasing the cost and complexity of the system.
Thus there is a need for a sample loading system that overcomes the limitations described above, making it easy and quick to load samples onto an automated analyzer without interrupting analyzer operation. There is also a need for a sample loading system that allows for the easy introduction of a limited number of samples onto the analyzer without placing the samples onto a large capacity turntable or carousel.